Mining roof bolting machines have previously utilized either ineffective or dangerous methods for retaining the roof bolt drill steel during initial stages of drilling operation in a substantially vertical orientation during the collaring of the drill steel in the mine roof. Collaring is achieved when the drill steel and bit have entered the mine roof to an extent of approximately nine inches to one foot. Once collared, the supporting system for the drill steel is no longer necessary because of the retentive force the roof provides to the upper portion of the drill steel.
Past operations have utilized the dangerous practice of having the roof bolt operator hold and guide the drill steel during the collaring process. This has been inefficient and dangerous from two standpoints. First, there is the danger that the hand of the roof bolt operator may be caught between the drill steel and the roof bolter, thereby causing unnecessary injury to the operator himself. Secondly, the mine operator may be in a position in which he does not retain the drill steel in a substantially vertical direction thereby causing an angular drilling of the roof bolt hole and possible danger to the drill steel, or, alternatively, the drilling of a substantially non-vertical hole in the mine roof. Various methods have been attempted in the past to retain the drill steel at the upper portion of the drill head without success. For the most part, these previous methods have employed devices which must be mechanically removed once the drill has been collared.